BURDOCK 693 



places in the United States and Canada. The fleshy root is collected 

 in autumn from plants of the first or second year's growth, and care- 

 fully dried. 



Description. Nearly cylindrical, slightly tapering, or broken 

 and split longitudinally into pieces, 10 to 20 cm. in length, 5 to 20 

 mm. in diameter; externally, bark dark brown, longitudinally 

 wrinkled, with few rootlets or rootlet-scars, crown somewhat annulate 

 from scars of bud-scales and sometimes surmounted by a soft, woolly 

 tuft of leaf -remains having unicellular, twisted hairs; fracture short, 

 horny when dry, tough when damp ; internally light brown, radiate, 

 bark 2 to 3 mm. in thickness, wood porous, cambium zone distinct; 

 odor slight; taste mucilaginous, slightly bitter. 



Old woody roots in which the pith is more or less obliterated 

 and which have been collected from the fruiting plant should be 

 rejected. 



Inner Structure. Periderm consisting of thin-walled, brownish, 

 rectangular cork cells; cortex consisting of inulin-containing paren- 

 chyma, the inner layer having narrow strands of leptome; cambium 

 distinct; xylem composed of narrow wedges, made up mostly of 

 wood parenchyma, and a few thin-walled wood fibers and wide 

 tracheae, separated by broad medullary rays; the wood paren- 

 chyma and medullary rays contain inulin in the form of highly refrac- 

 tive, irregular masses., varying from 0.006 to 0.045 mm. in length; 

 tracheae from 0.050 to 0.150 mm. in width, and marked by numerous 

 narrow, simple pores, and occasionally accompanied by narrow thin- 

 walled wood fibers. Tissues of the pericycle and primary, cortex 

 are commonly seen in the outer layers of the bark. The outer cor- 

 tical region of young roots, shows an interrupted circle of resin canals, 

 which are wanting in older roots. 



Powder. Light yellow; parenchymatous cells with irregular 

 crystalloidal masses of inulin; tracheae few, having long slit-like 

 simple pores occasionally associated with a few narrow sclerenchy- 

 matous fibers. 



Constituents. Inulin about 45 per cent; about 0.07 per cent of 

 a volatile oil; a bitter principle; about 0.04 per cent of a fixed oil; 

 tannic acid; mucilage; a sugar; and ash, about 5 per cent. 



The fruits of Lappa contain a bitter crystalline alkaloid, lappine; 

 1.15 per cent of a resin; and 15.4 per cent of a light yellow fixed oil. 

 Trimble and Macfarland, Amer. Jour. Pharm., 1885, p. 127. 



ARNICA RADIX. Arnicae Rhizoma Arnica Root. The rhizome 

 and roots of Arnica montana (see Arnica fl ores) . The well-developed, 

 rather fleshy rhizomes are gathered in the fall and carefully dried. 



